Magnitude and Determinants of CD4 Recovery After HAART Resumption After 1 Cycle of Treatment Interruption

OBJECTIVE: The extent of immune reconstitution following HAART resumption after 1 cycle of treatment interruption (TI) is not well known. METHODS: Multicenter retrospective analysis of patients who discontinued HAART with a CD4 > 500 cells/microL. Cox proportional hazards models were used to identify prognostic factors for immunologic response after treatment resumption. CD4 trends were investigated using linear mixed models. RESULTS: One hundred and eighty-three individuals were included. Median CD4 at TI and at treatment restart were 748 and 459 cells/microL, respectively. Median time from TI to treatment restart was 5.52 months. Ninety percent of the patients reached an undetectable viral load. One hundred and twenty-five subjects experienced immunologic response; 66 patients reached their pre-TI CD4 levels. At 3, 6, 12, and 24 months after treatment restart, the median CD4 increase was 149, 153, 161, and 178 cells/microL, respectively. Subjects with less steep CD4 declines during TI tended to have a lower initial CD4 increase, as did those reinitiating HAART with viral loads < 5000 copies/mL, whereas subjects who had experienced a virologic response to their initial HAART regimen had slower CD4 increases. CONCLUSIONS: Patients willing to discontinue treatment should be advised that immune reconstitution to pre-TI values is possible in fewer than 50% of patients at 2 years after treatment restart.